Tolbutamide and Atenolol: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 15, 2026 · Source data updated Jul 11, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Tolbutamide
Atenolol
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
Tolbutamide lowers your blood sugar to treat diabetes, and atenolol is a beta-blocker used for blood pressure or heart issues. When taken together, two things can happen. First, your blood sugar could swing a bit lower or higher than usual. Second, and more importantly, atenolol can hide some of the warning signs of low blood sugar. One of the earliest clues, a fast or pounding heartbeat, may be blunted, so a low might sneak up on you.
The good news is that you may still feel other warning signs like sweating or dizziness, and your care team can manage this easily by checking your sugar a little more often. Keep taking both as prescribed and talk with your pharmacist or doctor.
Effect: Beta-blockade may alter glycemic control (hypo- or hyperglycemia) and can mask adrenergic warning signs of hypoglycemia, particularly tachycardia. Sweating and dizziness are typically preserved.
Mechanism: Altered glucose metabolism plus beta-adrenergic blockade blunting the sympathetic counter-regulatory response. Atenolol is beta-1 selective, so risk is generally lower than with nonselective agents, but the effect can still occur. Neither drug is a prodrug.
- Direction: Variable glycemic effect; blunted hypoglycemia awareness (tachycardia).
- Onset: Delayed. Evidence: Probable. Severity: Moderate.
- Management: Increase glucose monitoring frequency; individualize sulfonylurea dose. If atenolol is discontinued, watch for loss of glycemic control.
What happens
Hypoglycemia or hyperglycemia; decreased symptoms of hypoglycemia
Interaction Deep Dive
When antidiabetic medications are taken together with beta-blockers, the result may be either hypoglycemia or hyperglycemia, and the combination can also mask the warning signs of hypoglycemia23. Tachycardia may be influenced, though other hypoglycemic manifestations, including dizziness and sweating, are not 1. Insulin-induced hypoglycemia can be intensified by nonselective beta-blockers, which may also impede the return of serum glucose to normal levels. In patients who have both heart failure and diabetes, hyperglycemia may worsen 7. It may become necessary to monitor glucose more often or to adjust the dose of the antidiabetic drug 23. During combined use, watch carefully for signs and symptoms of hypoglycemia, and should the beta-blocker be discontinued, monitor for a loss of glycemic control 4.
Why it happens (mechanism)
Altered glucose metabolism and beta blockade
How to manage this interaction
Keep taking both medications as prescribed. This combination is manageable with a few simple steps.
- Your care team may have you check your blood sugar more often, especially when starting, stopping, or changing either drug.
- The dose of your diabetes medicine may need to be adjusted and individualized by your team based on your readings.
- Because atenolol can mask a fast heartbeat, pay attention to other low-sugar signs like sweating, shakiness, hunger, or dizziness.
- If atenolol is ever stopped, tell your team so they can watch for your sugar climbing.
Raise any lows or highs, or new symptoms, with your pharmacist or prescriber.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
2 reports — tap to read
a) Among elderly diabetic patients receiving either insulin or sulfonylureas, the specific antihypertensive agent selected had minimal impact on the risk of hypoglycemia; however, once other risk factors were accounted for, the lowest risk was seen with cardioselective beta blockers and the highest with non-cardioselective beta blockers, while other antihypertensive agents fell in between (N=13,559) 5.
b) In patients with hypertension and non-insulin dependent diabetes, beta blockers, but not alpha blockade or ACE inhibitors, produced a worsening of long-term glycemic control. Beta blockade also led to some unfavorable changes in the lipid profile. These effects were particularly pronounced with propranolol. Using an alpha blocker together with the beta blocker prevented the worsening attributable to beta blockade 6.
Common questions
Can I take Tolbutamide and Atenolol together?
Taking tolbutamide with atenolol can shift your blood sugar and hide the racing-heart warning of a low, so monitor your sugar more closely and watch for sweating or dizziness. Your care team can manage this by adjusting your diabetes dose and monitoring. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Tolbutamide and Atenolol interaction?
It is rated moderate. Can be significant — usually manageable with monitoring.
How quickly could this interaction happen?
The documented onset is "delayed". Effects tend to build up gradually over days to weeks.
How is the Tolbutamide and Atenolol interaction managed?
Keep taking both medications as prescribed. This combination is manageable with a few simple steps. Your care team may have you check your blood sugar more often, especially when starting, stopping, or changing either drug. The dose of your diabetes medicine may need to be adjusted and individualized by your team based on your readings. Because atenolol can mask a fast heartbeat, pay attention to… Management is individual — always follow your own care team's guidance.
How strong is the evidence for this interaction?
The evidence is graded "probable". Good supporting evidence, though not definitively proven.
Questions for your pharmacist
- Does my dose of Tolbutamide or Atenolol need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there anything you'd monitor while I'm on both?
References (7)
- Product Information: TENORMIN(R) oral tablets, atenolol oral tablets. AstraZeneca Pharmaceuticals LP (per FDA), Wilmington, DE, 2012. DailyMed
- Product Information: TOUJEO(R) subcutaneous injection, insulin glargine subcutaneous injection. sanofi-aventis (per manufacturer), Bridgewater, NJ, 2015. DailyMed
- Product Information: AMARYL(R) oral tablets, glimepiride oral tablets. Sanofi-Aventis U.S. LLC (per FDA), Bridgewater, NJ, 2013. DailyMed
- Product Information: Glynase(R) PresTab(R) oral micronized tablets, glyburide oral micronized tablets. Pharmacia & Upjohn Co (per FDA), New York, NY, 2013. DailyMed
- Shorr RI, Ray WA, Daugherty JR, et al: Antihypertensives and the risk of serious hypoglycemia in older persons using insulin or sulfonylureas. JAMA 1997; 278:40-43. DOI
- Whitcroft IA, Thomas JM, Rawsthorne A, et al: Effects of alpha and beta adrenoceptor blocking drugs and ACE inhibitors on long term glucose and lipid control in hypertensive non-insulin dependent diabetics. Horm Metab Res Suppl 1990; 22:42-46.
- Product Information: COREG CR(R) extended-release oral capsules, carvedilol phosphate extended-release oral capsules. GlaxoSmithKline, Research Triangle Park, NC, 2011. DailyMed
Keep reading about Tolbutamide
Keep reading about Atenolol
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